The present invention relates to a method for manufacturing a seal at a shaped body, especially at the cylinder head of a vehicle motor, wherein the cylinder head is a diecast member and has a bearing groove for receiving the seal and wherein the seal is applied under pressure, and also relates to a pressing device for applying a seal to a shaped body, especially a cylinder head of a vehicle motor in which the cylinder head comprises a bearing groove for the seal.
It is known to apply a seal, for example, at a cylinder head comprised of a diecast member of a vehicle motor, by applying with a cartridge gun or any other application device sealing material, for example, silicone elastomer, into the bearing groove of the cylinder head under high pressure in order to anchor the seal as securely as possible within the bearing groove.
From German Offenlegungsschrift 30 18 074 it is known to apply a silicone elastomer seal in one or more layers, to allow the solvent to evaporate at room temperature, and to thus realize the curing of the seal.
The problem with such seals is that for a required manufacturing speed, as it is, for example, necessary in the automobile industry, bubbles will form within the seal which destroy the sealing properties of the seal. Thus, it is known to apply considerable pressures, for example, a pressure of 60 bar. Such a pressure, however, requires not only a correspondingly stable support of the cylinder head gasket which is comprised of formed sheet metal or preferably also comprised of a diecast member. The high pressure pressing device required for application of the seal is also very expensive and complicated especially since the application must be automated. All joints etc. of the application arm must thus withstand the high pressure whereby, however, the precision of the shape may not be neglected.
It is furthermore known to produce the seal as an extruded profile whereby numerous shapes for the design of the seal have become known. For example, such seals are known from German Offenlegungsschrift 24 37 567 and German Offenlegungsschrift 25 51 360. The material to be used is selected such that it is substantially resistant in the presence of oil as well as in the presence of acidic components that are contained within old oil. However, hot and thus low viscosity oils have the tendency to creep under the seals especially when diecast cylinder heads are being used which have, in general, a substantially greater surface roughness than sheet metal covers.
It is therefore an object of the present invention to provide a method for manufacturing a seal at a shaped body as well as a pressing device with which a permanent sealing action even with respect to low viscosity oils and diecast shaped bodies are provided whereby, however, the manufacture should require only little expenditures while, at the same time, the required precision-related specifications and precision should be maintained.